- 70% enhancement in efficiency in TFSC
- Applicable to CIS and a-Si cells
- enables thinner cells
- reduces material costs
- 4th generation Solar cells
In conventional (1st and 2nd generation) solar cells, their anti-reflecting coating (ARC) represent multilayer structures prepared with nanometer precision which, allows the almost complete absorption of the solar irradiance by the PV layer. As a result, overall efficiency of available solar cells attains 20%.
3rd and 4th generation solar cells are based on Thin Film Solar Cells (TFSC) technology to offer the significantly lower-cost electric energy source. It is not reasonable to apply such ARCs for the enhancement of TFSCs since starting from 5-7 layers the cost of an ARC per unit area becomes higher than the cost of the TFSC. State of the art is to apply a simplest ARC – blooming layer (as a rule of silicon nitride).
To fabricate efficient solar cells with a very small thickness, (ARC) should be replaced by a light-trapping structure (LTS), since ARCs cannot prevent reduction of the solar cell efficiency. The blooming layer is not as efficient in preventing the reflection losses as the multilayer ARC. Also, it does not trap the light. Therefore, to attain at least additional 5-7% for the overall PV efficiency one has to use rather thick photovoltaic layers (800-1000 nm). This corresponds to TFSCs, whose PV layers are only 5-6 times thinner than those of typical wafer-type solar cells of the 2nd generation. This limits the commercial potential of TFSC technologies
The invention introduces detailed light trapping structure is developed by nanoantenna design. Structure of nanoantenna is developed to achieve level of 5-7% overall efficiency in 300-500 nm thick PV layer.
Device and structure is theoretically modeled and profoundly simulated. Preliminary manufacturing tests of the antenna structures are conducted.
Professor Constanin Simovski, Department of Radio Science and Engineering, School of Electrical Engineering
Phone: +358 50 594 7050